Treatment of vinyl type halides



?atented July 25, 1944 gaunt umrao sures carom oer-"ice 2,354.51: ram'rrmur or vmrr. mp mamas Hairy 66 v. ma. Berkeley, and Kenneth E. Marple, Oakland, calm, assignoro to Shell Development Company, San

Francisco, Call! a corporation oi Delaware No Drawing. Application June 8, 1942, Serial moment 10 Claims. (in; eco -seal This invention relates to the treatment of unsaturated halides and more particularly-pertains to the production of carbonyl compounds, 1. e., compounds comprising an aldehyde and/or a ketone roup, from non-tertiary vinyl-type halides containing at least fdur carbon atoms.

The process of the, invention is preferably executed by reacting a non-tertiary vinyl-type halide containing at least four carbon atoms with an aqueous solution comprising a strong monoor polybasic mineral acid-acting ,oxyacid, and separating the carbonyl compound thus produced from the reaction mixture. The process may also be executed by .first contacting m nomtertiary vinyl-typ halide containing at leastlfour carbon atoms with a strong monoor polybasic mineral acid-acting oxyacid in th substantial amence of water, the carbonyl compound being thereafter formed upon subsequent treatment of the reaction mixture with water.

The nature of the carbonyl compound obtained '7 by reacting a non-tertiary vinyl-type. halide with or more-halogen atoms in addition to the halogen atom or'atoms contained in one or more oi the p above groupings comprised therein.

The vinyl-type halides to which the prose process is applicable are non-tertiary, that is, they contain a vinylic groupingwherein neither of the f vinylic carbon atoms is tertiary, l. e.', attached .1

to three other carbon atoms. Hence a compound comprising grouping V, supra, alone is unsuited for th purpose'oi the invention. Theterm "nontertiary as used herein and in the appended claims is intended to exclude such compounds. It is to be understood, however, that the treated compound may comprise a vinylic grouping wherein one oi! the vinylic carbon atoms is tertiary if it also contains a vinylic grouping wherein the vinvlic carbon atoms are either primary or a mineral acid-acting oxyacid according to the process of the invention is dependent upon the structure of the particular: halide or halides treated.

Vinyl-type halides are distinguished from nonrinyl-type unsaturated halides in that they contain at least one halogen atom which is attached may be properly designated a vinyl-type halide, while the term vinylic carbon atom" may be applied to either of the unsaturated carbon atoms in each grouping. The grouping may comprise part of an isoor normal alkyl chain which may or may not be attached to a cyclic radical as of' the aromatic, alicyclic, and heterocyclic series or may comprise part of an alicyclic structure. The

7 organic compoundmay or may not contain one secondary, i. e., connected ooonly one or two other carbon atoms, but in general it is preferred to execute the process with vinyl-type halides do void of tertiary vinylic carbon atoms. The treated compound may, 01 course. contain one or more non-vinylic tertiary carbon atoms. A suitable group oi vinybtype halides includes, among others, compounds such as the following together with their homgiogues, analogues and suitable substitution products. I

Hal

:It should be understood that in the vinyl-type halides treated the hydrogen atoms other than those included in the vinylic groupings may be 7 process depends upon the. structure of the vinyl ass-1,512

type halide treated. For example, if the treated halide comprises grouping I, that is, the group H Hal wherein the halogenated vinylic carbon atom is a secondary carbon atom, the overall reaction results in the formation of a ketonic compound.

0n the other hand, should the treated compound contain a primary halogenated vinylic carbon atom, i. e., a halogenated vinylic carbon atom which is attached to only one other carbon atom, namely the vicinal vinylic carbon atom, the reaction according to the invention results in the formation of an aldehydic compound.

When the compound subjected to treatment contains a plurality of halogenated vinylic carbon atoms including a primary halogenated vinylic carbon atom, a product may be obtained which is both aldehydic and ketonic, while the presence in the treated compound of a plurality of secondary halogenated vinylic carbon atoms may result either in the production of a com.- pound containing a like number of ketone groups, or of a halogenated ketone, depending upon whether the halogenated vinylic carbon atoms are vicinal. In the case of a compound such as Hal Hal R$=J3R only one of the halogens wilL-iingneral, be split 0!, so that the product will ordinarily be a halogenated ketone,

- Hal 0 Halogenated carbonyl compounds are also obtainable .by the process of the invention, by the treatment of compounds comprising one or more halogen atoms attached to carbon atoms other than the vinylic carbon atoms contained therein. Compounds containing a vinylic carbon atom of tertiary character, which compounds do not also contain a vinylic grouping wherein the carbon atoms are either primary or secondary, when treated according to the invention'do not give carbonyl compounds but rather halohydrins, and

hence are without the scope thereof as previously herein stated.

The invention may be executed employing a wide variety of strong mineral acid-acting oxy-' acids. Among the many suitable acids may be mentioned the strong mineral oxyacids, 3:801, HPOa, HaSaOl. HdPaOn, HsPOr. H.1P04, HePaOr; the aromatic sulfonic acids such as benzene sulfonic acid, and the halo-sulfonic acids, particularly chlorosulfonic and bromo-sulfonic acids. When operating with the halo-sulfonic acids the treated halide is first contacted with the acid in' 60% to about 96%, according to the preferred mode of executing the invention. The best results are usually obtained with those aqueous to less than about 25%, preferably to solutions containing from 80% to 90% H2804. When lower acid concentrations are used, the reaction may proceed too slowly and incompletely for general practical purposes. The use of sulfuric acid in concentrations in excess of about 90% is disadvantageous in some cases due to the occurrence of undesirable polymerization and condensation reactions, but it is often possible to offset this effectby operating at lower temperatures and/orby-shortening the contact time. when acids other than sulfuric are used, such acids may be applied in corresponding-concentra- H1804. A convenient method of effecting the dilution comprises the slow addition of the retio'ns depending on their strength and activity as compared to sulfuric acid. The use of weaker acids may require the employment of higher operating temperatures.

It is preferred to eifect the reaction of a suitableunsaturated halide'and a suitable aqueous mineral acid-acting oxyacid at a temperature at which the reaction proceeds rapidly with a minimum of polymerization. The reaction is preferably effected in a temperature range of from about C. to about 0., although in some cases temperatures substantially above this range (up to 60 C.) may beadvantageously applied. The optimum reaction temperature will usuaiinbe dependent on the specific reactants,

the concentration and strengthof the acid appliedand/or the contact time of the reactants;

- To avoid polymerization losses due to local overheating, it is preferred to slowly add the aqueous acid to the unsaturated halide. The reaction is usually exothermic, the heat liberated usually necessitating cooling of the reaction mixture. Agitation of the reaction mixture is advantageous since it may afford more efllcient conaction mixture to a mixture of ice and/or water,

the ice'and/or water being presentjin an amount suihcient to reduce the acid concentration to the desired value. The resulting carbonyl compound may be recovered from the relatively dilute acidic mixture in a wide variety of suitable manners, depending upon the specific carbonyl compound to be recovered and on the particular taste of the operator. 7

While the present process has been referred to. herein as executable by either one of two modes, it willbe understood that the invention is not limited to such modes of execution. For example, a modified method of operation may be employed wherein the treated halide is subjected to. the action'of the mineral acid-acting oxyacid in the presence of only enough water to effect partial conversion thereof to the desired carbonyl product, the reaction mixture being thereafter.

treated with sufiicient additional water to convert'the remainder of the halide to product.

product is best preceded by dilution ofthe reence of a suitable inert organic compound such as an ester, hydrocarbon, halogenated hydrocarbon, and the like, in general such practice is.

proportion of about 1 mol thereof for each vinylic grouping present in'the treatedhalide. This practice results in the most complete utilization of acid, although higher conversions may besttained with little loss of yieldby using an excess of acid. Under the preferred conditions of operation, that is, by operating with 80% to 90% action mixture, preferablywith water, to an acid concentration of between about 25% to 75%.

In many cases it is preferred to recover the car-- bonyl compound by subjecting the diluted acidic reaction mixture to a distillation or fractionation ucts as might occur at the kettle temperature necessary to effect the distillation at atmospheric pressure. If desired. the dilute acidic reaction mixture may be neutralized by the addition of an equivalent amount of a suitable basic substance. In general, the reaction product may be j recovered from the aqueous acidic or neutral re- .ployed to recover the'carbonyl compound from aqueous sulfuric at a temperature within the range of from about 20 C. to about 40 0., a contact time of onehour is normally sufllcient for a high conversion and yield of the desired product.

When the process of the invention is executed by first contacting the unsaturated halide with the selected oxyacid in the substantial absence of water, that is, with an essentially anhydrous acid, or with an anhydrous solution of the acid in an inert solvent, formation of the desired carbonyl product may be subsequently effected by diluting the reaction mixture with water. The temperature of the reaction mixture before and during the dilution is preferably maintained at or below about 20 C. but permissiblv at any temperature below about 40 C. Usually, where sulfuric acid has been employed, enough water is added to the the condensate if the condensate comprises besides the carbonyl product other constituents, for example, water and/or unreacted halide. I

In the-recovery of methyl ethyl ketone from the reaction mixture resulting from reacting 2- chlorobutene-2 with sulfuricacid and water ac-v cording to the preferred method of executing the invention, it has been found desirable to strip the reaction mixture subsequent to dilution with steam. By such practice'sulfuric acid of a conceiitration of from 10% 'to 50%, suitable for reconcentration and re-use, can be recovered without dimculty from the bottom of the stripping oolumn. The steam distillation is best conducted under a reduced pressure where the acid concentration-of the reaction mixture is greater than 60%; The top. product from the stripper consists of a mixture of methyl ethyl ketone,.

water, unreacted 2-ch1orobutene-2 and a minor amount of polymer.- -These may be separated. for example, by extracting the ketone with a suitable solvent, such ashot water, or by fracreaction mixture to reduce its acid concentration (6 tionation.

The present process is of particular value as applied to eifect'the conversion of z-chlorobutene-2, which is a cheap by-product material for which few mes are known and which is available in largequantities, to methyl ethyl ketone,

an. excellent low boiling solvent which may be substituted in many instances for relatively more.

expensive solvents. The anhydrous hydrogen chloride produced as a result of the reaction between 2-chlorobutene-2 and sulfuric acid is easily recoverable and finds ready application, for example, in the manufacture of molecular chlorine according to the Deacon process and modiilcations thereof.

The following examples, introduced in illustration of the process of the invention as applied to the production of methyl ethyl ketone from fl-chlorobutene-il, are not to be construed as limiting the invention to the treatment of this speciiic vinyl-type halide or to the conditions of operation disclosed Eromple I Approximately 4 mols or Z-chlorobutene Z,

Ol I cni-d=on -cm were charged to a glass flask fitted with a stirrer. About 5 mols of aqueous sulfuric acid of a concentration of about 84% was then added to the flask as quickly as possible. The reactants were permitted to remain in contact for about one hour, the H01 evolved being caught in a water s'crubber. The very small amounts of other'gases produced were discarded. Upon expiration of the contact period during which the average temperature 'within the reactor was 28. 0., the mixture in the flask was diluted with water to an acid concentration of about 60% on an organicfree basisand stripped with steam without reflux in a continuously operated column, the reaction mixture being fed to the top of the column, the steam. being introduced at the bottom thereof. Analysis of the product from the stripper revealed that about 64% of the 2-chlorobutene-2 had been converted to methyl ethyl ketone. The yield of methyl ethyl ketone on the basis of the reacted chloride was between 84% and 85%.

Example [I The experiment of Example I was again repeated, the treated chloride being diluted to fifty weight per cent with a synthetic octane solvent. An excess of acid was used (5 mols 84% acid to 3.18 mols of 2-chlorobutene-2) Other conditions were substantially the same. 0.69 mol of the chloride did not react. 'Theyield of methyl ethyl ketone on the basis of the-reacted chloride was about 87%.

. trample IV A continuous reactor consisting of a packed column cm. long by 4.5 cm. in diameter was employed. About 7% mols of undiluted 2-chlorobutene-2 was continuously passed into the bottom of the column .while about 8% mols of 84% aqueous sulfuric acid was continuously introduced at the top. The average column temperature was about 30' 0., while the rate of material feed was so regulated as to give a contact time of the reactants of roughly 60 minutes. After the reaction was started all of the unreacted z-chloro- ,butene-Z was carried out as vapor with the hydrogen chloride. 3.86 mols of anhydrous H01 were recovered. The reaction mixture withdrawn from the bottom of the column was collected and subsequently steam stripped. The rim resulted in a- 70% conversion of the z-chlorobutene-2 and an yield of methyl ethyl ketone.

We claim as our invention:

l. A process for the production of methyl ethyl ketone which comprises reacting 2-chlorobutene-2 with aqueous sulfuric acid of a concentration between about 80 and about per cent at a temperature in the range of from about 20C. to 40 0., diluting the reacted mixture with water to a sulfuric acid concentration between about 25 the diluted reacted mixture to separate methyl ethyl ketone therefrom.

3. A process for preparing methyl ethyl ketone which comprises reacting 2-chlorobutene-2 with a concentrated aqueous solution of a strong mineral oxyacid at a temperature not substantially above 60 C. for a sumcient period of time to convert a substantial portion of the 2-chlorobutene-2 to methyl ethyl ketone, and recovering the methyl ethyl ketone.

4. A process for the production of methyl ethyl ketone which comprises reacting 2-chlorobutene-2 with sulfuric acid.

5. A process for the production of methyl ethyl atoms, wherein the oleflnic carbon atoms are of the group consisting of primary and secondary oleflnic carbon atoms. and wherein at least one of the oleiinic carbon atoms is directly. linked to a halogen atom, with aqueous sulfuric acid of a concentrationbetween about 60% and 90% at a temperature not substantially above 80 C. for a suiiicient period of time to convert a substantial portion of the oleflnic halide to a carbonylic compound, diluting the reacted mixture with water to an acid concentration below about 25%, and steam distilling the diluted mixture to separate the carbonylic product.

8. A process for the production of a carbonylic compound which comprises reacting a mono-oleilnic halide which contains at least four carbon atoms, wherein the oleflnic carbon atoms are of the group consisting of primary and secondary oleiinic carbon atoms, and wherein at least one of the oleilnic carbon atoms is directly linked to a halogen atom, with a. concentrated aqueous solution of a strong mineral oxy acid.

9. A process for the production of a carbonylic compound which comprises reacting a mono-olefinic halide which contains at least four carbon atoms, wherein the oleflnic carbon atoms are of the group consisting of primary and secondary olefinic carbon atoms, and wherein at least one of the olefinic carbon atoms is directly linked to 10 a halogen atom, with a concentrated aqueous so lution of sulfuric acid.

HARRY DE V. FINCH. 

